钻进速度对钻屑温度影响的实验研究

利用钻屑温度预测冲击地压时,钻进速度是影响钻屑温度的一个重要因素。本文利用自行研制的钻头温度测试装置,对钻头温度变化进行监测,分析不同钻进速度对钻头温度变化的影响规律。实验结果表明:钻孔时,钻进速度减慢,钻头与孔壁之间的摩擦时间增长,摩擦产生的热量增多,使钻头温度升高。钻进速度对钻屑温度有较大影响,使用钻屑温度法预测冲击地压时,应制定统一的钻进速度指标,增加预测准确性。     

Optical properties of polymer poly（phthalazinone ether sulfone ketone） film waveguide

The optical properties of novel polymer poly（phthalazinone ether sulfone ketone, PPESK） film waveguide are studied by prism coupler. The optical properties of PPESK-8020, including refractive index, birefringence, thermo-optical coefficient and optical loss, are demonstrated. This kind of material has the advantages of low optical loss （less than 0.24 dB/cm at 1310 nm and 0.52 dB/cm at 1550 nm） and high thermal stability （1% weight loss temperature： 488 ℃）. Due to these excellent properties, it may have great potential in optical waveguide applications.     

电子战用功率行波管

介绍了电子战装备中宽带行波管及微波功率模块的特点,概括了宽频带、小体积、高效率功率行波管的现状和发展趋势。分析了电子对抗用宽波束的单元功率特点,讨论了弹载、无人机等对高效率、大功率、耐高温行波管放大器的需求。详细介绍了国内外新一代超小型化行波管及模块的最新进展。     

基于超材料的新型低剖面谐振腔天线

根据法布里-珀罗谐振腔理论,设计并测试了一款新型双S 低剖面天线。该天线采用加载超材料表 面的方法,用以降低法布里天线的谐振距离。理论分析发现,双S 型超材料表面在特定频段内具有负相位特性,根据 法布里-珀罗谐振条件可以降低谐振腔体天线的剖面。实验结果证明,天线的谐振距离降低至姿/ 12. 7,远远小于传 统天线的姿/ 2。     

Tunable terahertz acoustic-phonon emission from monolayer molybdenum disulfide

The acoustic-phonon emission from monolayer molybdenum disulfide (ML-MoS₂) driven by a direct-current electric field is studied theoretically using the Boltzmann equation method. It is found that the Cerenkov emission of terahertz acoustic-phonons can be generated when a very weak electric field is applied to ML-MoS₂. The physical mechanisms of acoustic-phonon emission are analyzed from the perspective of condensed matter physics. The acoustic-phonon emission from ML-MoS₂ is also compared with those from graphene and GaAs. The results reveal that the frequencies of acoustic-phonons generated by ML-MoS₂ are between the frequencies of those generated from GaAs and graphene. The results of this work suggest that the ML-MoS₂ can make up for graphene and GaAs in respect of acoustic-phonon emission and be used in tunable hypersonic devices such as terahertz sound sources.     

一类时滞分数阶计算机病毒模型的稳定性研究

本文研究一类改进的时滞分数阶计算机病毒模型正平衡点的稳定性问题.利用线性化方法和拉普拉斯变换获得模型对应的线性化系统的特征方程,通过讨论特征方程的根以及横截条件研究时滞和正平衡点稳定性之间的关系,推导了Hopf分支出现时时滞临界值的计算公式,并选择恰当的系统参数进行数值模拟以验证理论分析的合理性.     

惯导设备用导电滑环瞬断故障分析研究

瞬断是表征精密导电滑环性能的主要性能指标,其具有出现概率低、时间短、难以检测的特点,但却又极易对系统造成不确定的影响,直接关系到系统信号传输的可靠性。对惯导设备转台调制过程中出现航姿跳变故障原因进行分析,通过搭建检测系统复现导电滑环的瞬断现象,指出外界微小异物进入环槽必定会导致具有刷丝对称双接触特点的导电滑环产生瞬断现象,从而导致航姿跳变故障的发生,且使导电滑环出现不可逆转的损伤。